Endoscopic instrument

ABSTRACT

An endoscopic instrument is provided and includes a housing including an elongated shaft assembly extending distally therefrom. The elongated shaft assembly includes inner and outer shaft members. The inner and outer shaft members are removably coupled to the housing and the outer shaft member is movable with respect to the inner shaft member. An end effector is operably supported at the distal end of the outer shaft member and includes a pair of jaw members configured for treating tissue. A bushing operably couples to the inner and outer shaft members of the shaft assembly and selectively and releasably couples to the housing. The bushing includes one or more mechanical interfaces configured to engage one or more slots defined through the inner shaft member and one or more slots defined through the outer shaft member to release the inner and outer shaft members from the housing.

CROSS REFERENCE TO RELATED APPLICATION

The present application claims the benefit of and priority to U.S. Provisional Application Ser. No. 61/677,348, filed on Jul. 30, 2012, the entire contents of which are incorporated herein by reference.

BACKGROUND

1. Technical Field

The present disclosure relates to endoscopic instruments and, more particularly, to endoscopic instruments including selectively removable shaft assemblies.

2. Background of Related Art

Endoscopic instruments are well known in the medical arts. For example, an electrosurgical endoscopic forceps (a closed forceps) is utilized in surgical procedures, e.g., laparoscopic surgical procedure, where access to tissue is accomplished through a cannula or other suitable device positioned in an opening on a patient. The endoscopic forceps, typically, includes a housing, a handle assembly including a movable handle, a shaft and an end effector assembly attached to a distal end of the shaft. The end effector includes jaw members configured to manipulate tissue, e.g., grasp and seal tissues. The endoscopic instrument may be configured to utilize one or more types of energies including, but not limited to, RF energy, microwave energy, ultra sound to treat tissue.

Another type of endoscopic instrument that may be utilized in laparoscopic surgical procedures is an ultrasonic endoscopic forceps. The ultrasonic endoscopic forceps is similar in configuration to the electrosurgical endoscopic forceps. Unlike the electrosurgical endoscopic forceps, however, the ultrasonic endoscopic forceps utilizes ultrasonic energy to treat tissue.

As is conventional with both of the above endoscopic instruments, the shaft of these instruments is, typically, rigidly attached to the endoscopic instrument, i.e., the shaft is non-removable from the housings of the respective instruments. Having an endoscopic instrument with a non-removable shaft may prove problematic during the operative life cycle of the endoscopic instrument. For example, if the endoscopic instrument is to be re-used, the entire device is, typically, sterilized via an autoclaving process or the like. As can be appreciated, sterilizing an endoscopic instrument with the shaft including the end effector attached may prove difficult. In particular, it may prove difficult to sterilize between small spaces of the shaft, e.g., spaces at a distal end of the shaft adjacent the end effector.

SUMMARY

In view of the foregoing, it may prove advantageous in the medical arts to provide endoscopic instruments that include selectively removable shaft assemblies.

In the drawings and in the descriptions that follow, the term “proximal,” as is traditional, will refer to an end which is closer to the user, while the term “distal” will refer to an end that is farther from the user.

As used herein, “endoscopic instrument” generally refers to any surgical instrument that is configured for access into a body cavity. The endoscopic instrument may be configured to grasp tissue or may be configured to grasp and subsequently electrosurgically treat tissue, e.g., an electrosurgical endoscopic device. In the latter instance, the endoscopic instrument may be configured to couple to one or more suitable electrosurgical energy sources. Or, the endoscopic instrument may be battery powered. As it is used herein, “electrosurgical procedure” generally refers to any electrosurgical procedure involving any form of energy, such as, for example, microwave energy, radiofrequency (RF) energy, ultrasonic energy, thermal energy or combination thereof.

An aspect of the present disclosure provides an endoscopic instrument. The endoscopic instrument includes a housing including an elongated shaft assembly extending distally therefrom. The elongated shaft assembly has inner and outer shaft members. The inner and outer shaft members are removably coupled to the housing and the outer shaft member is movable with respect to the inner shaft member. An end effector is operably supported at the distal end of the outer shaft member and includes a pair of jaw members configured for treating tissue. A bushing may be operably coupled to the inner and outer shaft members of the shaft assembly and configured to selectively and releasably couple to the housing. In certain instances, the bushing may include one or more resilient fingers that are configured to engage one or more slots defined through the inner shaft member and one or more slots defined through the outer shaft member to release the inner and outer shaft members from the housing. In certain instances, slot(s) on the outer shaft member is/are longer than the slot(s) on the inner shaft member to allow the outer shaft member to translate with respect to the inner shaft member.

A spring carrier includes one or more resilient bosses that are configured to releasably engage one or more second slots defined through the outer shaft member at a proximal end thereof to release the inner and outer shaft members from the housing when the outer shaft member is rotated with respect to the spring carrier. The spring carrier is configured to provide axial movement of the outer shaft member when a handle assembly of the endoscopic instrument is actuated. In certain instance, the resilient boss(es) includes a chamfered edge that is configured contact an edge of the corresponding second slot to move the resilient boss(es) out of engagement with the corresponding second slot when the outer shaft member is rotated. The spring carrier may include a plurality of radial slots on a distal face thereof. The plurality of radial slots are configured to engage a corresponding plurality of mating features disposed on an interior wall of the housing when the spring carrier is in a forward-most position within the housing. Engagement between the plurality of radial slots and corresponding plurality of mating features prevents rotation of the spring carrier when outer shaft member is rotated.

An aspect of the present disclosure provides an endoscopic instrument. The endoscopic instrument includes a housing that includes an elongated shaft assembly extending distally therefrom. The elongated shaft assembly has inner and outer shaft members. The inner and outer shaft members are removably coupled to the housing and the outer shaft member is movable with respect to the inner shaft member. An end effector is operably supported at the distal end of the outer shaft member. A bushing is operably coupled to the inner and outer shaft members of the shaft assembly and is selectively and releasably coupled to the housing. The bushing includes a generally annular groove located at a proximal end thereof. A latch is operably disposed on the housing and is movable with respect thereto for selectively and releasably engaging the annular groove on the bushing to release the inner and outer shaft members from the housing.

The latch may include a pair of opposing arms. Each of the opposing arms may include a respective detent that seats within a corresponding pocket disposed within an interior wall of the housing. The detents may be seated within the pockets and configured to limit movement of the latch.

The latch may include an aperture that is configured to receive the bushing and the outer shaft member therethrough. Moreover, the latch may include a generally elongated slot therein that is configured to engage a corresponding detent disposed on a locking member that is positioned proximal the latch and movable therewith. In this instance, the locking member may be configured to couple the outer shaft member to a spring carrier configured to provide axial movement of the outer shaft member when a handle assembly of the endoscopic instrument is actuated. The outer shaft member may include a flange disposed at a proximal end thereof that is configured to engage the locking member.

An aspect of the instant disclosure provides an endoscopic instrument. The endoscopic instrument includes a housing that includes an elongated shaft assembly extending distally therefrom. The elongated shaft assembly has inner and outer shaft members. The inner and outer shaft members are removably coupled to the housing and the outer shaft member is movable with respect to the inner shaft member. A rotating assembly is operably coupled to the housing and is configured to rotate the inner and outer shaft members. A bushing is removably coupled to the rotating assembly and is operably coupled to the inner and outer shaft members and selectively and releasably coupled to the rotating assembly. An end effector is operably supported at the distal end of the outer shaft member. The bushing includes one or more mechanical interfaces that are configured to engage one or more slots defined through the inner shaft member and at least one slot defined through the outer shaft member to release the inner and outer shaft members from the housing.

The mechanical interfaces of the bushing may be in the form of one or more resilient fingers. In this instance, the at least one slot on the outer shaft member is longer than the at least one slot on the inner shaft member to allow the outer shaft member to translate with respect to the inner shaft member.

A spring carrier may be provided and may include at least one resilient boss. The resilient boss may be configured to releasably engage at least one second slot defined through the outer shaft member at a proximal end thereof and configured to release the inner and outer shaft members from the housing when the outer shaft member is rotated with respect to the spring carrier. The at least one resilient boss may include a chamfered edge that is configured to contact an edge of the corresponding second slot to move the at least one resilient boss out of engagement with the corresponding second slot when the outer shaft member is rotated. The spring carrier may be further configured to provide axial movement of the outer shaft member when a handle assembly of the endoscopic instrument is actuated. The spring carrier may include a plurality of radial slots defined on a distal face thereof. The plurality of radial slots may be configured to engage a corresponding plurality of mating features disposed on an interior wall of the housing when the spring carrier is moved to a forward-most position within the housing. Engagement between the plurality of radial slots and corresponding plurality of mating features prevents rotation of the spring carrier when outer shaft member is rotated.

The mechanical interfaces of the bushing may be in the form of one or more detents. In this instance, the bushing may include a generally annular groove that is located at a proximal end thereof.

A latch may be operably disposed on the housing and may be movable with respect thereto for selectively and releasably engaging the annular groove on the bushing to release the inner and outer shaft members from the housing. The latch may include a pair of opposing arms. Each of the opposing arms may include a respective detent that seats within a corresponding pocket disposed within an interior wall of the housing. The detents may be seated within the pockets and configured to limit movement of the latch. The latch may include an aperture that is configured to receive the bushing and the outer shaft member therethrough. The latch may include a generally elongated slot therein that is configured to engage a corresponding detent disposed on a locking member positioned proximal the latch and movable therewith. The locking member may be configured to couple the outer shaft member to a spring carrier configured to provide axial movement of the outer shaft member when a handle assembly of the endoscopic instrument is actuated. The outer shaft member may include a flange that is disposed at a proximal end thereof that is configured to engage the locking member.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments of the present disclosure are described hereinbelow with reference to the drawings, wherein:

FIG. 1 is a side, perspective view of an endoscopic instrument including a selectively removable shaft assembly according to an embodiment of the present disclosure;

FIG. 2 is a side, perspective view of a proximal end of the shaft assembly depicted in FIG. 1 shown unattached from a housing of the endoscopic instrument;

FIG. 3 is a perspective view of a bushing that couples to inner and outer shaft members and to the housing of the endoscopic instrument;

FIG. 4 is a perspective view of a spring carrier that couples to the outer shaft member depicted in FIG. 2;

FIG. 5 is a side, perspective view of a selectively removable shaft assembly and bushing coupled thereto according to another embodiment of the instant disclosure;

FIG. 6 is a side view of an endoscopic instrument including the selectively removable shaft assembly and bushing depicted in FIG. 5;

FIG. 7 is an isometric view of the endoscopic instrument depicted in FIG. 6 with a latching mechanism shown in a latched configuration;

FIG. 8 is a side view of the of the endoscopic instrument depicted in FIG. 6 with the latching mechanism shown in a unlatched configuration;

FIG. 9 is an isometric view of the endoscopic instrument depicted in FIG. 8 with the latching mechanism shown in a unlatched configuration; and

FIG. 10 is the isometric view of FIG. 7 with the latching mechanism removed to illustrate the position of the neighboring components of the latching mechanism when the latching mechanism is in the latched configuration.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Detailed embodiments of the present disclosure are disclosed herein; however, the disclosed embodiments are merely examples of the disclosure, which may be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present disclosure in virtually any appropriately detailed structure.

As noted above, it may prove useful in the medical arts to provide an endoscopic instrument that includes a selectively removable shaft assembly. In accordance with the instant disclosure, a selectively removable shaft assembly that may be configured for use with a variety of endoscopic surgical instruments is provided. The selectively removable shaft assembly includes a unique bushing configuration that couples to inner and outer shaft members of the shaft assembly to allow a user to remove the inner and outer shaft members from a housing of the endoscopic instrument. The unique bushing configuration also allows axial translation of the outer shaft member with respect to the inner shaft member.

With reference to FIG. 1, an endoscopic instrument 2 that utilizes a selectively removable shaft assembly 4 according to an embodiment of the instant disclosure is illustrated. For illustrative purposes, the endoscopic instrument 2 that is configured for use with the shaft assembly 4 is a battery powered ultrasonic instrument 2 (e.g., an ultrasonic forceps 2). Briefly, forceps 2 includes a housing 6 that is configured to house one or more components, e.g., transducer, waveguide and electrical circuitry that is configured for electrical communication with a battery assembly 8 of the forceps 2. A proximal end of housing 6 is configured to releasably couple to an ultrasonic generator 10 and the battery assembly 8. A distal end of the housing 6 is configured to support and releasably couple to a proximal end 12 (FIGS. 1 and 2) of shaft assembly 4 that is releasably positionable within a rotating assembly 13. Shaft assembly 4 extends from housing 6 and defines a longitudinal axis “A-A” therethrough (FIG. 1). A distal end 14 of the shaft assembly 4 is configured to support an end effector 16 thereon. The operational parts of end effector 16 (e.g., jaw members 18 and 20) are movable relative to one another upon actuation of a movable handle assembly 22 coupled to housing 6.

In the illustrated embodiment, jaw member 20 serves as an active or oscillating blade and is configured to treat tissue. An activation button 24 places the forceps 2 in one or more modes of operation and generator 10 is configured to convert electrical energy produced by the battery assembly 8 into ultrasonic energy. More particularly, generator 10 includes a transducer (not explicitly shown) that is configured to convert electrical energy to mechanical energy that produces motion in a waveguide (not explicitly shown) that is in operative communication with the active jaw member 20.

With reference now to FIG. 2, the proximal end 12 of the shaft assembly 4 is illustrated to show the operative components of the shaft assembly 4. Shaft assembly 4 includes inner and outer shaft members 26 and 28 respectively. In the illustrated embodiment, the inner shaft member 26 encases an ultrasonic shaft (not explicitly shown). Unlike outer shaft member 28 which is movable axially along the longitudinal axis “A-A” to move jaw member 18, inner shaft 26 is fixed as it does not move axially to move jaw member 18. Rather, inner shaft 26 supports pivot points (not explicitly shown) for jaw member 18 to open and close. The ultrasonic shaft member is rigidly coupled to the housing 6 and is configured to house one or more components of the forceps 2, e.g., the waveguide and/or transducer therein. In some embodiments, however, the ultrasonic shaft may be configured to releasably couple to the housing 6.

Outer shaft member 28 is configured to support the jaw members 18 and 20 thereon (FIG. 1) and is configured to releasably couple to one or more components, e.g., a spring carrier 42 (FIG. 4), of the housing 6. Thus, after use, the inner shaft member 26 and outer shaft member 28 (including the jaw members 18 and 20 supported thereon) may be removed from the housing 6 so that the housing 6 including the ultrasonic shaft may be sterilized. As noted above, outer shaft 28 moves axially along the longitudinal axis to open and close jaw member 18.

One or more slots 30 are defined through the inner shaft member 26 and are aligned with one or more corresponding first slots 32 defined through the outer shaft member 28 (FIG. 2). Slots 30 and 32 may include any suitable configuration. In the illustrated embodiment, slots 30 and 32 include a generally elongated configuration. In accordance with the instant disclosure, slots 30 are smaller in length than slots 32, as best seen in FIG. 2. Providing slots 30 with a smaller length allows the outer shaft member 28 to move axially a predetermined distance with respect to the inner shaft member 26 to move the jaw member 18 from an open configuration (FIG. 1) to a closed configuration (not explicitly shown). Specifically, slots 30 are completely filled by resilient fingers 34 on bushing 36 to restrict axial movement of inner shaft member 26. First slots 32 are longer than slots 30 to allow axial movement of outer shaft member 28 to move jaw member 18 from the open configuration to closed configuration. As can be appreciated, first slots 32 can be sized to limit a maximum opening of jaw member 18.

With reference to FIG. 3, a bushing 36 is illustrated including a base 38 and an elongated stem 41 extending distally therefrom. Bushing 36 is configured to fixedly couple to the inner and outer shaft members 26, 28. Accordingly, corresponding mechanical interfaces (e.g., resilient fingers 34) are disposed on stem 41 and are biased radially inward therefrom to engage slots 30 and 32 on the respective inner and outer shaft members 26, 28.

Base 38 is configured to key the bushing 36 to the rotation of the rotating assembly 13. Accordingly, base 38 includes a plurality of planar surfaces 38 a (or splines not explicitly shown) that are configured to engage corresponding surfaces of the rotating assembly 13. In the embodiment illustrated in FIG. 3, the base 38 includes eight (8) planar surfaces 38 a forming a generally octagonal configuration.

An aperture 40 of suitable configuration extends through the bushing 36 and is configured to receive the outer shaft member 28 therethrough for coupling the outer shaft member 28 to the spring carrier 42 (FIG. 4).

Spring carrier 42 includes a generally elongated proximal end 44 of suitable configuration that is configured to support a spring (not explicitly shown) thereon (FIG. 4). One or more resilient bosses 50 (one resilient boss 50 illustrated in the drawings) extend radially inward from the elongated proximal end 44 (FIG. 4) and are configured to releasably couple to one or more corresponding slots 52 disposed at the proximal end 12 of the outer shaft member 28 (FIG. 2). The resilient bosses 50 include a chamfered edge 53 (FIG. 4) that is configured to facilitate engaging and disengaging the outer shaft member 28 with the spring carrier 42. In particular, as the outer shaft member 28 is rotated (e.g., counter-clockwise) an edge 15 (FIG. 2) of the outer shaft member 28 that defines the slots 52 cams the resilient boss 50 outwardly.

Spring carrier 42 also includes a generally circumferential distal end 46 that is configured to engage an internal wall (not explicitly shown) of the housing 6. In particular, a plurality of radial slots 54 are formed in a distal face 56 of the spring carrier 42 and are configured to engage corresponding mating features (not explicitly shown) on the internal wall of the of the housing 6. More particularly, when the movable handle 22 is moved proximally, the spring carrier 42 is moved distally toward the distal end of the housing 6 (e.g., the spring carrier 42 is moved to an extreme forward position) and into engagement with the mating features on the internal wall of the housing to “lock” the spring carrier 42 and prevent the spring carrier 42 from rotating with the outer shaft member 28.

In use, after a surgical procedure, e.g., an ultrasonic sealing procedure, has been completed, the bushing 36 including the inner and outer shaft members 26, 28 may be removed so that the housing 6 and ultrasonic shaft coupled thereto may be completely cleaned and re-sterilized by an autoclave. In one embodiment, the moveable handle 22 is moved proximally to move the spring carrier 42 to the extreme forward position to lock the spring carrier 42 as described above. With the spring carrier 42 in the locked position, the outer shaft member 28 may be rotated, e.g., in a counter-clockwise direction, to disengage the resilient bosses 50 from the slots 52 of the outer shaft member 28. Once the resilient bosses 50 are disengaged from the slots 52, the bushing 36 including the inner and outer shaft members 26, 28 may be uncoupled from the housing 6.

To re-attach the bushing 36 including the inner and outer shaft members 26, 28 (or in some embodiments, a new bushing 36 including new inner and outer shaft members 26, 28 with new seals), the bushing 36 including the inner and outer shaft members 26, 28 may be slid over the ultrasonic shaft and the outer shaft member 28 may be reinserted into the spring carrier 42. Once inserted into the spring carrier 42, the outer shaft member 28 may be rotated, e.g., in a clockwise direction, to engage the resilient bosses 50 with the slots 52 of the outer shaft member 28.

The unique configuration of the bushing 36 and shaft assembly 4 of the present disclosure enables a user to quickly and easily couple and uncouple the bushing 36 including the inner and outer shaft members 26, 28 from the housing 6 of the forceps 2 for sterilization of the forceps 2.

With reference to FIGS. 5-10 a shaft assembly 104 according to an alternate embodiment of the present disclosure is illustrated. Forceps 102 and shaft assembly 104 are substantially similar to forceps 2 and shaft assembly 4. In view thereof, only those features unique to the forceps 102 and/or shaft assembly 104 are described in detail.

Unlike outer shaft member 28, outer shaft member 128 includes a proximal flange 129 of suitable configuration (FIG. 5). Proximal flange 129 is configured for engagement with a “guillotine” type locking member 131 that is operably coupled to a spring carrier 142 (FIGS. 6, 8 and 10) to couple the outer shaft member 128 to the spring carrier 142. In one embodiment, the locking member 131 slides over a front face 133 (FIG. 5) of the proximal flange 129 to couple the outer shaft member 128 to the spring carrier 142. This method for coupling the outer shaft member 128 to the spring carrier 142 allows the proximal flange 129 to freely rotate behind the locking member 131 such that the spring carrier 142 does not rotate with the outer shaft member 128.

Locking member 131 includes a bottom portion with a generally “C-shaped” configuration that rests on an outer surface of the outer shaft member 128, see FIG. 10 for example. This “C-shaped” configuration allows the locking member 131 to move in and out of engagement with the outer shaft member 128 and allows the outer shaft member 128 to move axially with the spring carrier 142.

A top portion 135 (FIGS. 6, 8 and 10) of the locking member 131 includes a detent 137 (FIGS. 6-10) that is configured to engage a corresponding aperture 139 (FIG. 7) on a latch 141 (FIGS. 6-9). The detent 137 and aperture 139 couple the locking member 131 to the latch 141 to allow the locking member 131 and latch 141 to move in unison.

The latch 141 is operably disposed in the housing 106 and is accessible to a user from a top portion of the housing 106. The latch 141 also includes an aperture 143 of suitable configuration that allows passage of the bushing 136 including the outer shaft member 128 therethrough (FIGS. 7 and 9).

An interior wall 151 (FIGS. 7 and 9) that defines the aperture 143 is configured to releasably engage an annular groove 145 (as best seen in FIG. 5) disposed at a proximal end 147 of the bushing 136. In particular, pulling the latch 141 a predetermined distance (e.g., upwards) disengages the interior wall 151 from the annular groove 145 and disengages the flange 129 from the locking member 131 so that the bushing 136 including the inner and outer shaft members 126, 128 may be uncoupled from the spring carrier 142. Likewise, pushing the latch 141 a predetermined distance (e.g., downwards) engages the interior wall 151 with the annular groove 145 and engages the flange 129 with the locking member 131 so that the bushing 136 including the inner 126 and outer shaft members 128 may be coupled to the spring carrier 142.

Unlike bushing 36 that includes a pair of resilient fingers 34, the bushing 136 includes a pair of mechanical interfaces (e.g., detents 134) that are configured to engage corresponding slots 130 and 132, see FIGS. 5, 6 and 8; in these figures, the detent 134 is shown engaged with the slot 130 and as such the slot 130 is not explicitly shown.

A guide slot 152 (FIG. 5) is provided to replace slot 52 of the outer shaft member 28 and is configured to engage a corresponding detent 156 that extends from the spring carrier 142 (FIG. 9). This configuration of the guide slot 152 and detent 156 facilitates aligning the annular groove 145 and the inner wall 151 of the locking member 131.

A stop member 158 (FIGS. 6 and 8) defined on an interior surface of the housing 106 is provided and is configured to contact the top surface 135 of the locking member 131 when the latch 141 has been pulled a predetermined distance (e.g., upwards), see FIG. 8 for example; this prevents a user from “over-pulling” the latch 141.

In some embodiments, such as the one illustrated in FIGS. 5-10, the latch 141 includes an optional pair of opposing arms 153 that each include a respective detent 155 (see FIG. 9 for example) that seats within a corresponding pocket (not explicitly shown) disposed within an interior wall of the housing. The detents 155 seated within the pockets are configured to further limit movement of the latch 141.

In use, to uncouple the bushing 136 including inner and outer shaft members 126, 128 from the housing 106, a user pulls the latch 141 (e.g., upwards) to disengage the locking member 131 from the proximal flange 129 and the latch 141 from the annular groove 145.

Once disengaged, the bushing 136 including inner and outer shaft members 126, 128 may be uncoupled from the housing 106.

To re-couple the bushing 136 including inner and outer shaft members 126, 128 to the housing 106, the user re-inserts the bushing 136 including inner and outer shaft members 126, 128 into the housing 106 and pushes the latch 141 (e.g., downwards) to engage the locking 131 member with the proximal flange 129 and the latch 141 with the annular groove 145.

As described above with respect to the bushing 36 and shaft assembly 4, the unique configuration of the bushing 136 and shaft assembly 104 of the present disclosure enables a user to quickly and easily couple and uncouple the bushing 136 including the inner and outer shaft members 126, 128 from the housing 6 of the forceps 102 for sterilization thereof.

From the foregoing and with reference to the various figure drawings, those skilled in the art will appreciate that certain modifications can also be made to the present disclosure without departing from the scope of the same. For example, and as noted above, the ultrasonic shaft may be configured to couple and uncouple with the bushings 36, 136 including inner and outer shafts 26, 126 and 28, 128, respectively. In this instance, one or more components associated with the forceps 2, 102 may be utilized in conjunction with the shaft assemblies 4, 104. For example, in one particular embodiment, a rear knob 3 (FIG. 1) may be utilized to release the ultrasonic shaft. In this instance, the rotating assemblies 13, 113 are held immobile while the rear knob 3 is turned to unscrew the ultrasonic shaft. Once the ultrasonic shaft is unscrewed, it along with the shaft assemblies 4, 104 may be uncoupled as described above.

While several embodiments of the disclosure have been shown in the drawings, it is not intended that the disclosure be limited thereto, as it is intended that the disclosure be as broad in scope as the art will allow and that the specification be read likewise. Therefore, the above description should not be construed as limiting, but merely as exemplifications of particular embodiments. Those skilled in the art will envision other modifications within the scope and spirit of the claims appended hereto. 

What is claimed is:
 1. An endoscopic instrument, comprising: a housing including an elongated shaft assembly extending distally therefrom, the elongated shaft assembly having inner and outer shaft members, the inner and outer shaft members removably coupled to the housing and the outer shaft member movable with respect to the inner shaft member; an end effector operably supported at a distal end of the outer shaft member; and a bushing operably coupled to the inner and outer shaft members of the shaft assembly and selectively and releasably coupled to the housing, wherein the bushing includes at least one resilient finger that engages at least one slot defined through the inner shaft member and at least one first slot defined through the outer shaft member; and a spring carrier operably supported within the housing and including at least one resilient boss that releasably engages at least one second slot defined through the outer shaft member at a proximal end thereof, the at least one resilient boss being disengaged from the at least one second slot to release the inner and outer shaft members from the housing when the outer shaft member is rotated with respect to the spring carrier, the spring carrier further configured to provide axial movement of the outer shaft member when a handle assembly associated with the housing is actuated, wherein the spring carrier includes a plurality of radial slots defined on a distal face thereof, the plurality of radial slots engage a corresponding plurality of mating features disposed on an interior wall of the housing when the spring carrier is moved to a forward most position within the housing, wherein engagement between the plurality of radial slots and corresponding plurality of mating features inhibits rotation of the spring carrier when the outer shaft member is rotated, thus facilitating release of the inner and outer shaft members from the housing.
 2. An endoscopic instrument according to claim 1, wherein the at least one first slot of the outer shaft member is longer than the at least one slot of the inner shaft member such that when the resilient finger of the bushing engages the at least one first slot of the outer shaft member and the at least one slot of the inner shaft member, the outer shaft member is able to translate with respect to the inner shaft member.
 3. An endoscopic instrument according to claim 1, wherein the endoscopic instrument is an ultrasonic instrument configured to ultrasonically treat tissue.
 4. An endoscopic instrument according to claim 1, wherein the at least one resilient boss includes a chamfered edge that is configured to contact an edge of the corresponding second slot to move the at least one resilient boss out of engagement with the corresponding second slot when the outer shaft member is rotated relative to the spring carrier.
 5. An endoscopic instrument, comprising: a housing including an elongated shaft assembly extending distally therefrom, the elongated shaft assembly having inner and outer shaft members, the inner and outer shaft members removably coupled to the housing and the outer shaft member movable with respect to the inner shaft member; a rotating assembly operably coupled to the housing and configured to rotate the inner and outer shaft members; a bushing removably coupled to the rotating assembly and operably coupled to the inner and outer shaft members and selectively and releasably coupled to the rotating assembly; an end effector operably supported at the distal end of the outer shaft member, wherein the bushing includes at least one mechanical interface that engages at least one slot defined through the inner shaft member and at least one first slot defined through the outer shaft member; and a spring carrier operably supported within the housing and including at least one resilient boss that releasably engages at least one second slot defined through the outer shaft member at a proximal end thereof, the at least one resilient boss being disengaged from the at least one second slot to release the inner and outer shaft members from the housing when the outer shaft member is rotated with respect to the spring carrier, the spring carrier further configured to provide axial movement of the outer shaft member when a handle assembly associated with the housing is actuated, wherein the spring carrier includes a plurality of radial slots defined on a distal face thereof, the plurality of radial slots engage a corresponding plurality of mating features disposed on an interior wall of the housing when the spring carrier is moved to a forward-most position within the housing, wherein engagement between the plurality of radial slots and corresponding plurality of mating features inhibits rotation of the spring carrier when the outer shaft member is rotated, thus facilitating release of the inner and outer shaft members from the housing.
 6. An endoscopic instrument according to claim 5, wherein the at least one mechanical interface of the bushing includes at least one resilient finger or at least one detent.
 7. An endoscopic instrument according to claim 6, wherein the at least one first slot of the outer shaft member is longer than the at least one slot of the inner shaft member such that when the resilient finger of the bushing engages the at least one first slot of the outer shaft member and the at least one slot of the inner shaft member, the outer shaft member is able to translate with respect to the inner shaft member.
 8. An endoscopic instrument according to claim 5, wherein the at least one resilient boss includes a chamfered edge that is configured to contact an edge of the corresponding second slot to move the at least one resilient boss out of engagement with the corresponding second slot when the outer shaft member is rotated relative to the spring carrier. 